Stud wrench



Patented July 25, 1950 Application March 1s, 194s, serial No. 15,575V soiaims, (ci. :i1-53) This invention relates to a tool for removing andreplacing threaded studs, and while more particularly designed for removing andfreplacing the cylinder head studs of automotive -engines,

it can be used wherever it is desiredvto obtain a.

rotating grip on a round rod or the like.

The principal object of the invention is to provide a-stud'wrench which will operateto firmly grip a variety of sizes of studs, and'fwhich can be employed to operatel in either directionso that the stud may be either unscrewed from place or screwed into place. f

Another object of the invention is vto so construct the device that it will operate ina=-mini mum of space, and so that it can operate with a variety of other wrenches, su-ch as socket wrenches, monkey wrenches, bar wrenches, and

the like.

A further object is to eliminate all screws, rivets, bolts, and nuts in a socket wrench construction, and to provide a wrench which can be readily assembled and dis-assembled.

(Sther objects and advantages reside in the detail construction of the invention, which is designed for simplicity, economy, and efficiency. 1

These will become more apparent from the following description.

In the following detailed: descriptionof l:the invention, reference is had to the accompanying drawing which forms a part hereof. Like numerals refer to like parts in all views of the drawing and throughout the description.

In the drawing:

Fig. 1 is a side elevation of an embodiment of the improved wrench, illustrating it in place on a typical stud;

Fig. 2 is a longitudinal section therethrough, taken on the line 2 2, Fig. 3;

Fig. 3 is a top plan view thereof; and

Figs. 4, 5, and 6 are cross-sections, taken on the lines 4--4, 5-5 and 6--6, respectively of Fig. 2.

In the drawings a conventional threaded stud is indicated at 9.

The improved wrench employs a hollow, cylindrical, drum-like housing Il) having a central stud opening II in its bottom and an open top. The open top of the housing is surrounded on the interior by a ring groove I2.

Three dogs I3 are pivotally mounted on pivot spins I4 extending downwardly through pin openings in the bottom of the housing Il). Each dog extends to a relatively pointed edge I5 at its free extremity, and two sets of teeth I6 incline from the pointed edge I5 to form a toothed, spearshaped head on the dog. The lengths of the dogs aresuchg that Iwhen swungitoa radial, position.: the three pointed edges I5 will extend substantiall to the axis of the housing I0. The pivotedgextremity ofeach dog is concentrically rounded about the `axis 'oi the pivot Apin y,I land 'rests-in ,a semi-cylindrical kreceiving socket Il in the housing Ill. lThe semi-cylindrical socket l1 forms the actual bearing for receiving the thrust of the dog.

A cam pin I8 extends yupwardly from each dog into a rotatabley camA plate I9 which rests upon the dogs I3. The cam'plate has a central opening 20 for the passageof the stud 9 and three equally spaced, radially extending cam slots 2 I, there being one of the slots 2| for each-.of the pinsll.I

It canfbe readily seen that if the cani plateis rotatedy back and forth, it will swing the dogsY lI3 -back and forth abouttheirpivotpins I4.l The `cam plate I9 is vrotated by means ofA an operating arm v22, which, in the embodiment illustrated, is a slotted screw ,extendingv into atappedopening in the camplate I9. The arm 22 extends through a circumferential, slot 23 in the housing. The slot is widenedat its exterior to facilitate the insertion of the usersn-ger against the arm- 22. Y

The housing I0 i;srotate d.by means of a hollow shank 24 having abottom` flange 25-which rests against` a shoulder 26' in the housing immediately above the cam plate I9. The ange is held in place by means of a spring ring 2l which expands outwardly into the ring groove I2. Three locking tongues 32 project from the circumference of the ange 25 into receiving notches 33 indented into the upper edge of the housing I3. The tongues act as keys to prevent relative rotation between the housing I0 and the shank 24.

The shank 24 may be provided with any type of wrench-receiving head. As illustrated, it is provided with hexagon wrench faces 28 on the exterior and a square socket 29 for receiving a socket wrench bar on the interior. It is also provided with diametrically extending bar openings 3Q for receiving a turning bar 3|.

Let us asume that it is desired to screw the stud 9 into place.l The improved wrench is placed over the stud, as shown in Figs. l and 4, the latter extending upwardly through the openings Il and 20 into the hollow interior of the shank 24. The operating arm 22 is swung clockwise in Fig. 3. This swings one face, which will be designated the left face, of each of the dogs I3 .against the stud, as shown in Fig. 4. The entire wrench is then rotated clockwise, as indicated by the arrow in Fig. 4 to screw the stud 9 into place.

To unscrew the stud 9, the wrench is removed therefrom and the operating arm 22 is swung to the broken line position in Fig. 3. This swings the studs clockwise about their pivots so as to y place them on the opposite sides of the stud as on. This end thrust is absorbed by the Contact' of the rounded ends of the dogs against therbotf toms of the receiving sockets Il without strain on the pivot pins I4.

While a specic form of the improvement has been described and illustrated herein, it is 'de sired to be understood that the saine may be varied, within the scope of the "appended claims, without departing from the spirit 'of the invention.

Having thus described the' invention what is claimed and desired secured by Letters Patent is:

l. A wrench for rotating-threaded studs comprising: a hollow, cup-like housing having a concentric stud opening in its bottom and an open top; a plurality of elongated dogs pivotally mounted at one end on said bottom at equally spaced intervals; a pointed, spear-shaped free extremity on the opposite end of each dog; teeth formed inthe opposite sides of each spearshaped extremity; a camL plate rotatably mounted in said housing'over said dogs; a pin projecting upwardly from each' of said dogs into a radially rextending slot in said camv plate; means for rotating said' cam plate fromv the exterior of said housing so'as to swing said dogs about their pivots; a hollow shank; a flange formed on thev lower extremity of said shank and fitting into the open top of said housing over said' cam plate; means for locking said ange in said housing; means for'preventing relative rotation between said flange and said housing; and wrenchengaging means on said shank. i

2'. A- wrench forrotatng threaded studs comprising: a hollow, cup-like housing having a con- 4 centric stud opening in its bottom and an open top; a plurality of elongated dogs pivotally mounted at one end on said bottom at equally spaced intervals; a pointed, spear-shaped free extremity on the opposite end of each dog; teeth formed in the opposite sides of each spear-shaped extremity; a cam plate rotatably mounted in said housing over said dogs; a, pin projecting up- ,Wardly from each of said dogs into a radially extending slot in said cam plate; means for rotating said cam plate from the exterior of said .housing so as to swing said dogs about their pivots; a hollow shank; a Iiange formed on the lower extremity of said shank and fitting into the open top of said housing over said cam plate; means for'locking said flange in said housing; and keys projecting radially outward on said angeinto receiving notches in said housing to transmit the rotation of said shank to said housing.

3. A wrench for rotating threaded studs oomprisingz a hollow; cup-1ike housing having a concentric sti-idI opening in: its bottom and an REFERENCES' CITED The following references are of recordin tlie le of this patent:

FOREIGN PATENTS Number Country Date 6,911' Great Britain of' 1902 636,996 France' Jan. 23,V 1928 39,434 FraudeA Aug. 1l, 1931 (Addition t0 NO. 636,996) 888,024 France Aug. 30;4 1943 565,376 Great Britain Nov.. 8, i944 

